Method of finishing metal sheets



May 12, 1942. A. E. HAMILTON METHOD OF FINISHING METAL SHEETS Filed Nov. 22, 1939 Patented May 12, 1942 UNITED STATES PATENT OFFICE nm'rnon oer-1132:1112 un'rsr. snnsrs I Alfred E. Hamilton, Pittsburgh, Pa. Application November 22, 1939, Serial No. 305,639 2 Claims. (01. za-is) Myinvention relates to the finishing of metalv sheets or strips, and more particularly to the ance, because the pickling operation produces a greyish cast on the surface 01' the strip, which often is so pronounced as to resemble a stippled eflect, and such appearance is not entirely eliminated by the cold-reducing rolls and the highly polished finishing rolls.

My invention has for its object the provision of a method of treating sheets whereby the said greyish cast or dull appearance is entirely eliminated, with the result that the sheets or strips are of more highly polished appearance than by the methods heretofore employed.

In the accompanying drawing the figure shows a schematic arrangement for practicing my invention.

It has been common practice to pass strips and sheets through pickling tanks and cold reducing rolls, in many instances the metal being also passed through scrubbing tanks after it leaves the pickling tanks. In the accomp y drawing, the metal strip to be treated is indicated by the numeral l and a pickling or scrubbingtank by the numeral 2. From the tank 2 the strip passes between a pair ofcold reducing rolls 3, which may be driven in any suitable manner, and which serve to eliminate surface roughness on the strip. The strip passes between pairs of abrasive rolls 4 and 5. These rolls are driven in any convenient manner and may rotate in directions counter to the movement of the strip, or. rotate in the same direction as the strip, but with a different rate of peripheral speed than the the speed at which the strip moves.

More than two pairs of abrasive rolls 4 and 5 will usually be provided, in order to give sufiicient abrasive capacity, and in order to avoid the necessity of frequent changes to provide 'iresh abrasive. The abrasive rolls which first engage the abrasive strip may carry abrasive 0! 240 grain size and the succeeding rells carry 400 grain abrasive, though the final abrasive, may be suitably be in the form of pneumatic cylinders provided with abrasive sleeves, as shown vtor example in my Patent No, 2,113,836.

One advantage of using the pneumatic rolls referred to, is that by'changing the air pressure within the.rolls, a desired degree oi'abrading pressure on the strip can be had. Also, the

abrading'surfaces of the rolls will yield to fol- I low uneven contours on the strip surfaces. It will also be understood that the strip can be passed directly from a pickling or scrubbing bath to the suriacing'rolls l and I.

The abrasive action oi! the rolls 4 and I is rather light as compared to heavy grinding operations. In many instances there will be only $5 or an inch removed from the strip, since the primary purpose of the abrasive action is to remove discoloration and any suchslight rou hness as remains after the strip passes through the reducing rolls 3. From the rolls 5 the. strip is carried through a tank} that contains water or other scrubbing liquid, wherein the sheet is scrubbed and washed by scrubbing rolls 1 to clear it of loose forei n matter. As the strip. I passes out. oi. the scrubbing tank, the major portion of the liquid is squeezed therefrom by the guide roller I! which may suitably be of rubber and by a rubber squeegee bar it, that extends crosswise of the strip and is so mounted as to exert substantial pressure thereon. The strip or. sheet i then passes rolls 8 .that are covered with felt or built up of circular fibrous discs. A polishing compound I will be employed with these rolls, numerous kinds highly polished. 1

of these compounds being well known on the market. Eventhough the strip which has a sur {ace of matte appearance, as tor example, unevenness such as is presenton an orange skin,

the low areas as well as the areas will be A pair oi rolls 8 covered with felt sleeves or brushes serve as wiping rolls to remove grit or particles ofpoIishing compound from the strip. l

The final finishing operation is performed .on the strip by a pair of rolls It that have a mirror finish, to give the-final desired high polish to the.

faces of the strip l. The strip is wound'upon a cient force, as through a friction drive, to coil the oi the fineness of flour. The abrasive rolls may strip'as it passes from the rolls in. The advancinzdnovement to the strip is imparted by the rolls 3 and ll.

A spool It carries a coil of paper l3. which is entered with the strip l upon the reel ii and is drawn from the spool as thesteei is wound upon the reel, so that it will prevent the turns of the steel l contacting and rubbing upon one another.

I claim as my invention:

1. The method 01' finishing cold-rolled sheets stsntislly in excess of that required for removing the roughness remaining alter cold-rolling. buillng the sheets to shright iinish, end thereafter rolling them by mirror-finished rolls.

2. The method of finishing cold-rolled sheets and the like, which comprises shrsding and polishing the surfaces thereof to s depth not substantisiiy in excess oi .002 inch, bumng the sheets to a bright finish, end thereafter rolling and the like, whichcomprises abrading and poll0 them by mirror-finished rolls.

ishing the surfaces thereof to a depth not subsnmsp n. lIAMIL'I'ON. 

